It has 4Gb of RAM, there's a trapdoor underneath to fit a hard disk or SSD. I am taking the one pictured out. This laptop is an older unit and not super fast, but I've had it running Windows 10 perfect.

Brand: Acer
Series: Aspire
Type: Notebook/Laptop
Processor: Intel Pentium
Screen Size: 15.6 in
Release Year: 2010
Model: Acer Aspire 5742
Hard Drive Capacity: 4 GB
Operating System: Not Included
Processor Speed: 2.20 GHz